High-voltage insulator.



PATENTED DEC. 5, 1905.

G. W. THOMAS.

HIGH VOLTAGE INSULATOR.

APPLICATION FILED SEPT. 7. 1904.

WITNESSES ATTORNEYS UNITED STATES PATENT OFFICE.

GEORGE W. THOMAS, OF EAST LIVERPOOL, OHIO, ASSIGNOR TO THE R.

THOMAS AND SONS COMPANY, OF EAST LIVERPOOL, OHIO, A CORPO- RATION OFOHIO.

HIGH-VOLTAGE INSULATOR.

Specification of Letters Patent.

Patented Dec. 5, 1905.

To all whom, it may concern.-

Be it known that I, GEORGE W. THOMAS, a citizen of the United States ofAmerica, residing in East Liverpool, in the county of O0- lumbiana,State of Ohio, have invented an Improved High-Voltage Insulator, ofwhich the following is a specification.

The object of my invention is to so construct an insulator especiallyadapted for high-voltage electric-transmission lines that it will resist tendency to deterioration from arcing or other electrical accidentsand at the same time will be able to stand the great mechanical strainsto which it is subjected.

In general practice high-tension petticoated insulators, whether ofporcelain or glass, are mounted on wooden pins, which with or withoutcentral ironbolts are fixed in cross-arms on the supporting-poles. Oneserious trouble eX- perienced with these Wooden pins is that when an arcforms across from the insulatorpetticoat it almost always jumps acrossto the point where the wooden pin joins upon the cross-arm and thewooden pin at that point becomes burned and loses both its mechanicalstrength and its electrical insulating power.

It is the main object of my invention to provide a construction whichwill enable me to dispense with this wooden pin and provide anon-combustible substitute which will at the same time have at leastequal mechanical strength.

In the accompanying drawings, Figure 1 is a vertical section of aninsulator constructed in accordance with my invention, and Fig. 2 is aview of a modification.

The main body of the insulator may vary considerably in construction andmay have any suitable number of petticoats without departing from myinvention. In Fig. 1, by Way of example, I have shown the body of theinsulator as made with two petticoats A and A and preferably in twoparts accordingly. These parts may be of porcelain or glass and may beunited by any suitable means, as by cement a, or, if of porcelain, bymeans of slip or glaze during the process of manufacture, as is wellknown.

Instead of constructing the central lower part of the insulator with afemale screwthread, as is common, for the reception of a correspondingmale thread upon the upper end of a wooden supporting-pin I provide asupporting pin or post B, of porcelain or glass or like vitreousmaterial, which I cement into the body of the insulator by suitablecementing material I).

One of the troublesome features in the manufacture of insulators is theformation of the usual carefully-formed female screw to receive thecorrespondingly-threaded wooden pin. This requires special forming-toolsand special skill on the part of the operator. By my invention theformation of this screwthread is avoided, for the central hole intowhich the supporting-post is to be cemented may be made plain or mayhave any roughlyformed projections, so that the manufacture ismaterially simplified. On the upper end of the supporting-post annulargrooves or screw-threads or other suitable projections I) may be formed,as indicated in Fig. 1, to give the needed holding-surface for thesecuringbody of cement.

The vitreous pin B is tubular and has passing through it a headed ironor other metallic bolt O, the head 0 of the bolt bearing upon the upperend of the vitreous post, while the other end of the iron bolt isthreaded and receives a nut and washer n, by means of which theinsulator, with its attached post, maybe secured to the usual cross-armD. (Indicated by dotted lines.) The head of the iron bolt may be of anyconvenient shape to form a shoulder and, if preferred, may be formed asat c, Fig. 2, by simply bending the upper end of the bolt over. Betweenthe shouldered head of the bolt and the top of the vitreous post B, Iprefer to provide acushion-washer c, which may be conveniently of fiber.The lower end of the vitreous post should be of sufficient diameter togive a broad bearingface where it rests upon the cross-arm. It does notenter into the cross-arm, and accordingly sidewise mechanical strainsare taken by the iron bolt and not by the post, as would be the casewere the vitreous post to pass down into a hole in the cross-arm.

In putting the parts together it is preferable to so apply the cementthat it -will also fill up crevices between the bolt and post.

I claim as my invention An insulator, comprising a petticoated bodyportion and a supporting-post, all of Vitreous I In testimony whereof Ihave signed my materiahthe supporting-post beingcemented name to thisspecification in the presence of to the body portion and having itslower end two subscribing Witnesses. a broad base adapted to rest on thecross-arm,

5 a metallic bolt assing through the post, and Witnesses:

having a shoul ered head bearing on the up- A. R. HOLMES, per end of thepost. B. D. KENNEY.

GEORGE W. THOMAS.

